Abstract: At least one corrosion protection unit is located adjacent to a region of a structure immersed in an electrolyte. Each corrosion protection unit includes a circuit for applying rectified alternating current voltage between the structure and electrodes in the electrolyte. Each corrosion protection unit includes Reference Cells to produce direct current voltage between the Reference Cells and the structure, a measuring circuit coupled to the Reference Cells for measuring the potential between the Reference Cells and the structure, and a control circuit for controlling the level of the rectified alternating current voltage in accordance with the measured potential levels. Corrosion protection units are independent of one another, so that independently established rectified alternating current voltages are applied between different regions of the structure and e first and second corrosion protection units.

Abstract: Communications systems are provided for use with an impressed current cathodic protection (ICCP) system having single or multiple ICCP components. A pipeline may be provided by connecting multiple pipeline sections together as an integrated pipeline where each section has an associated ICCP system. A communications signal comprising an AC signal is impressed on the pipeline and received by receivers associated with power supplies associated with each ICCP system. Upon reception of the AC signal, a controllable switch is operated within the power supplies to synchronously disconnect them from their power source and thereby enable accurate testing of the ICCP system.

Abstract: At least one corrosion protection unit is located adjacent to a region of a structure immersed in an electrolyte. Each corrosion protection unit includes a circuit for applying rectified alternating current voltage between the structure and electrodes in the electrolyte. Each corrosion protection unit includes Reference Cells to produce direct current voltage between the Reference Cells and the structure, a measuring circuit coupled to the Reference Cells for measuring the potential between the Reference Cells and the structure, and a control circuit for controlling the level of the rectified alternating current voltage in accordance with the measured potential levels. Corrosion protection units are independent of one another, so that independently established rectified alternating current voltages are applied between different regions of the structure and e first and second corrosion protection units.

Abstract: The present invention includes systems, methods and apparatus for continuously, independently and in some cases remotely monitoring the operation of a current interrupter used to test a cathodic protection system, or the cathodic protection system itself, for verification of proper operation. Embodiments of the invention include electronic devices that may be temporarily attached to a current interrupter that is being used to test a cathodic protection system, or directly to the cathodic protection system itself. Embodiments of the invention monitor the activity of an interrupter by sampling the output (voltage and time) to identify the cycle(s) of the interrupter. The invention provides truly independent verification since it does not need to know in advance the sequence or cycle times of the current interrupter being monitored. The information obtained by the invention is output so that it may be provided to a user, displayed, downloaded or stored for future reference.

Abstract: An active cathodic protection system, the apparatus comprising a rectifier element with at least one electrical connection to a source of electrical current, the rectifier element associated with a direct current positive (+) output terminal for electrical connection of via an anode connector to a consumable anode, a direct current negative (?) output terminal for electrical connection via a cathode connector to the structure to be protected, grounding means for electrical grounding of the apparatus and anti-cross connection means for preventing the continuing flow of electrical current when the anode connector is associated with the negative output terminal and the cathode connector is associated with the positive output terminal. The cathodic protection system also includes a microprocessor controlled device for shutting the system if an improper current is sensed.

Abstract: An electrode system for preventing biofouling of a surface either is applied directly onto the surface of an aquatic vehicle or structure, if the surface is non-conducting; or is applied onto an insulating paint layer on the surface, if the surface is conducting; or is embedded in a layer of electrically non-conducting material. The electrode system includes two alternating sets of electrodes in the form of spaced, parallel strips made from any conductive material, preferably a conductive coating, the first set being provided with a number n of parallel electrodes, and the second set being provided with a number n?1 of parallel electrodes, with the positions of the electrodes of the first set alternating with the positions of the electrodes of the second set. The geometry of the electrodes is such that when the voltage is applied, the electric field radiates outwardly parallel to the surface of the structure.

Abstract: First and second axial current meters (ACM) are mechanically connected to a well casing just above and below a corrosive zone and a master axial current meter (MACM) is connected to the casing at the earth's surface, the MACM periodically obtaining measurements of axial current from the ACMs to determine how much cathodic protection current is to be applied to the casing to avoid corrosion.

Abstract: A system using tank corrosion sensors to provide for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition in ships' tanks, and particularly in ships' seawater or compensated fuel tanks. The system includes reference half-cells mounted along a suspended cable and one instrumented sacrificial anode at the end of the cable to provide optimal sensing capability within a tank structure. The reference half-cells and the sacrificial anode measure a potential and current output, respectively. Together the measurements provide objective information that can be used to predict corrosion damage and coating deterioration occurring throughout the structure of the tank. The system may be used for an overall assessment and monitoring of the electro-chemical corrosion and coatings condition. In a preferred embodiment, the measurements are stored in a datalogger that is optimally contained within an associated instrument housing.

Abstract: An apparatus for prevention of corrosion in metal objects uses a capacitively coupled fastener or pad attached to a metal body being protected from corrosion. The metal body and the negative terminal of a source of DC voltage (battery) are grounded. The positive terminal of the source of DC voltage is connected to electronic circuitry that imparts pulses of low voltage DC through the capacitor to the fastener. These pulses of electrical current inhibit the oxidation of the metal object by providing a source of electrons to the oxidizing chemicals in contact with the metal. The electronic circuitry includes a reverse voltage protector to prevent the application of reverse source voltage. The circuitry also includes a power conditioner to supply a constant DC voltage to a microprocessor. The microprocessor generates pulses of DC signals that are amplified by a pulse amplifier and imparted to the conductive facing of the pad. For larger objects, a first and second cable are attached to a metal object.

Abstract: An apparatus for prevention of corrosion in metal objects uses a capacitively coupled fastener or pad attached to a metal body being protected from corrosion. The metal body and the negative terminal of a source of DC voltage (battery) are grounded. The positive terminal of the source of DC voltage is connected to electronic circuitry that imparts pulses of low voltage DC through the capacitor to the fastener. These pulses of electrical current inhibit the oxidation of the metal object by providing a source of electrons to the oxidizing chemicals in contact with the metal. The electronic circuitry includes a reverse voltage protector to prevent the application of reverse source voltage. The circuitry also includes a power conditioner to supply a constant DC voltage to a microprocessor. The microprocessor generates pulses of DC signals that are amplified by a pulse amplifier and imparted to the conductive facing of the pad. The invention also includes a battery voltage monitor and a power indicator.

Abstract: A cathodic protection system for protecting buried conducting structures, subject to corrosion such as well casings, pipe lines and the like, utilizes a plurality of pulsed D.C. current sources with the negative output terminal of each source connected to a separate structure and the positive output terminal of the sources connected to a common anode located near the structures. A control circuit synchronizes the operation of the several D.C. sources and sets the frequency and width of the output pulses. The amplitude of the output pulses from each D.C. source may be separately adjusted.

Abstract: In an electrically corrosion-proofing process in which the polarity of a metal member having a coating film is set at negative, the duration of setting the polarity of the metal member immersed in an aqueous solution of NaCl at negative is made discontinuous, and a positive-set duration in which the polarity of the metal member is set at positive, is interposed between a proceeding negative-set duration and a succeeding negative-set duration. The switching-over of the polarity is carried out by a polarity switch-over relay between the metal member and a DC power source. In the negative-set duration, the treatment for corrosion-proofing of the metal member is carried out, but the peeling-off of the coating film from a starting point provided by a damaged portion is produced. In the positive-set duration, an electrolytic product is produced in an exposed portion of the metal member, and the peeling-off of the coating film in the next negative-set duration is prevented by the electrolytic product.

Abstract: A cathodic protection test station device has a terminal board integrally formed with a base plate. A removable housing locks onto the base plate and covers the terminal board and the base plate. A tab formed in the base plate extends into a recess formed in the housing defining a locking position. A tool may be inserted in an access slot formed in the housing to deflect the tab and remove the housing. A plurality of first wedge members are symmetrically disposed on a bottom surface of the base plate. The first wedge members have an inclined surface that slidably engages an inclined surface of a plurality of second wedge members. A bolt extends through the base plate and the first and second wedge members to a nut held in a non-rotating manner in the second wedge member. As the bolt rotates, the nut moves towards a head of the bolt and urges the first and second wedge members axially together.

Abstract: The invention concerns a method for inhibition of growth of organisms on faces of constructions (11) submerged in a liquid. In themethod, an electrically conductive structure (11) to be protected is connected as the cathode of a source (14) of direct current, or an electrically non-conductive structure (111) to be protected is first coated with an electrically conductive material (111a) and connected as the cathode of a source of direct current (14), respectively, and, as the anode (12), an anode is used that has been isolated from the structure (11) to be protected or that is placed separate from said structure, which anode is connected as the anode of the source (14) of direct current.

Abstract: A cathodic protection system for protecting buried conducting structures, subject to corrosion such as well casings, pipe lines and the like, utilizes a plurality of pulsed D.C. current sources with the negative output terminal of each source connected to a separate structure and the positive output terminal of the sources connected to a common anode located near the structures. A control circuit synchronizes the operation of the several D.C. sources and sets the frequency and width of the output pulses. The amplitude of the output pulses from each D.C. source may be separately adjusted.